Our hypotheses is that 1. In patients with idiopathic dilated cardiomyopathy, administration of the cardiac tissue specific ace- inhibitor, quinapril, significantly suppresses angiotensin ii formation compared to enalapril. The suppression is more pronounced in patients with the ace d/d genotype and 2. The additional suppression of ang ii afforded by quinapril correlates with a reduction in left ventricular (lv) wall stress, transmyocardial norepinephrine, and the net balance of cardiac protein synthesis.